SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '02518522709cd8e1b460c65c1425666ea6208fdece01af85bef8f85306473eed' 
  AND token = '5p5KE1SmS+azHCfNtFMwMZRzD9jpgdeD4ROa5F8fn+4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}